Environmental pollution due to livestock excreta has become an increasingly large problem in recent years. In the past, various activated sludge apparatuses for organic waste fluid processing, including livestock wastes, have been proposed. The high cost of activated sludge apparatuses, however, makes it difficult for livestock raisers to employ them. Further, the handling of reactors used in the treatment process, the nutrition source/microorganism loading ratio, and selection of the mean residence time within the tank are difficult. The most difficult problem is an interference with sludge sedimentation due to increases of fibrous microorganisms. The maintenance of dissolved oxygen levels in the aeration tanks, the regulation of the cycling volume of activated sludge and the control of waste activated sludge are difficult. Fine bubbles are thought to be better in promoting the conveyance efficiency of oxygen. The distinction between fine and coarse is, however, ambiguous, making appropriate control impossible. Further, not only is the treatment time from the introduction of raw liquid to discharge lengthy; it also takes an inordinate amount of time to produce a non-offensive smelling and biochemically stable quality nutritious source. The establishment of an economical and structurally simple excretory liquid treatment system for livestock is still some time off; therefore, a dependence upon such primitive methods as natural decomposition using trench holes or aeration continues to be necessary.
Natural decomposition utilizing trench holes, however, causes ground water contamination, and forced aeration utilizing concrete frames requires an extended period of time to purify excretory liquid to effluent quality, making it an inefficient method due to the lengthy digestive time required by microorganisms.
The present invention alleviates the above mentioned problems by being non-polluting and by providing inexpensive organic liquid through an efficient purification system.